During normal operation of a motor vehicle, it is common that all four wheels might not be turning at an identical rate of speed. Different wheel turn rates are most commonly encountered when the vehicle is making a turn, but may also be caused by braking or non-uniform road surface conditions. In order to accommodate differing wheel turning rates while continuing to direct power to two wheels it is possible to provide a differential that allows for different wheel turn rates between the powered wheels. The differential allows the wheels to spin at different rates while delivering power to each wheel. While this solution may be satisfactory in some driving conditions, it is unsatisfactory under conditions where one of the powered wheels experiences a surface having a much lower coefficient of friction than a surface engaged by the other wheel(s). Such conditions may prevent the application of torque to a wheel with more traction, thereby resulting in undesired vehicle performance. A locking mechanism may be provided to lock the differential and prevent different wheel spin rates between two wheels in at least some circumstances.